1. Field of the Invention
There is a continuing interest in determining physiological compounds which are used for regulation of cellular functions. As these compounds are discovered and studied, a better understanding of the way organs function and communicate is obtained.
Pregnancy requires communication between the fetus and the host. The placenta serves as a barrier for transmission of various products produced by the fetus and/or the mother. Particularly, the bovine fetus is normally protected from the maternal immune system.
In many situations, particularly with domestic animals, which are frequently bred by artificial insemination, there is substantial interest in being able to detect at an early date the existence of pregnancy.
2. Description of the Prior Art
Butler et al., Biology of Reproduction (1982) 26:925-933 describes the detection and partial characterization of two bovine pregnancy-specific proteins. Butler et al., 1980 72nd Annual Meeting of the American Society of Animal Science, July 27-30, 1980, reported the isolation of two pregnancy-associated proteins from bovine placental membranes. Sasser et al., J. Anim. Sci. (1979) 49:333, Suppl. 1 (Abstract) reported placental-associated antigens during early pregnancy in the cow.